A number of blood glucose monitoring systems are available which generally include a blood glucose meter. The blood glucose meter can be configured to receive and read a test strip inserted therein on which a drop of a patient's blood has been deposited, or can be adapted for subcutaneous readings, for example.
Blood glucose meters generally comprise a memory for storing measured blood glucose values, along with other data such as the corresponding dates and times of day the values were measured. Blood glucose meters are generally also provided with a display screen, and user input buttons with which a user can specify which of the stored values to display.
Some blood glucose meters also provide statistical data relating to the stored measured blood glucose values such as 7-day, 14-day and 30-day averaging of glucose levels at one or more selected times of day (e.g., breakfast, lunch, dinner and nighttime). Examples of such blood glucose meters are Accu-check meters available from Roche Diagnostics USA and One Touch meters available from LifeScan. These blood glucose meters, however, are disadvantageous because the length of the period of time over which the averages are calculated is too long when a patient is using the averaging to adjust his insulin dosage, and particularly when the current average blood glucose values are too low.
The Ascensia Dex2 glucose meter available from Bayer Healthcare provides four daily averages, that is, averages of measured blood glucose values taken during a particular period of time such as a two hour window around a selected mealtime. No existing blood glucose meter, however, provides an average blood glucose value over a selected bin or period of time, as well as convenient access to the constituent values used to derive the average value and optionally an indication of variability among the constituent values. As will be described in more detail below, an indication of variability or at least knowledge of constituent values used to derive a mealtime average, is important information to have when adjusting insulin dosage.
Blood glucose monitoring can be combined with a diabetes management system comprising software (e.g., for installation on a personal computer (PC) or personal data assistant (PDA)) for collecting and analyzing meter readings and generating summaries and graphical results (e.g., pie charts, histograms and the like) to assist the patient in understanding trends in their blood glucose levels and insulin regimen. These systems, however, also do not provide a patient with immediate and convenient access to averages of blood glucose levels at a mealtime or during another specified time period and to the constituent levels used to generate these averages. For example, the One Touch diabetes management software available from LifeScan can provide mealtime averages in a computer generated logbook table; however, the measured levels from which the averages were calculated are merely provided by a separate glucose tracking time table on a different screen. Accordingly, it is not always clear to a patient as to which values are the constituent values of a particular average. This is disadvantageous when a patient is determining whether an adjustment is needed in his insulin dosage. This problem is illustrated by the following hypothetical situations.
By way of an example, if a lunchtime average was calculated at 180 mg/dl, and the constituent values of the lunchtime average were 162 mg/dl, 204 mg/dl and 174 mg/dl, a patient could safely increase the breakfast dose of a short acting insulin by a small amount since the constituent values had little variation. If, however, the constituent values varied significantly (e.g., were 75 mg/dl, 297 mg/dl and 168 mg/dl), the patient could not safely increase the breakfast dose of a short acting insulin, not even by a small amount. A patient would need to instead decide why there was so much variation, whether it be changes in diet, exercise or stress level. Thus, a need exists for a glucose monitoring device that provides a patient with convenient and immediate access to glucose level averages over relatively short periods of time and to the constituent values that generated the averages in order to make meaningful and timely decisions regarding his insulin regimen and other diabetes management techniques.